A Syrian refugee, suspected of having links to the Islamic State group, was arrested Thursday at a camp in Germany, a state prosecutor said, according to the Wall Street Journal. The arrest is likely to draw attention to the months-long debate over the open-door refugee policy followed by Germany as Europe witnesses the largest influx of asylum-seekers since the Second World War.

The man was reportedly registered as Leeth Abdalhmeed at the Unna-Massen refugee camp in the western part of the country, and was taken into police custody, the Journal reported, citing Sonja Frodermann, the state prosecutor in the city of Dortmund. Authorities suspect that Abdalhmeed, who was born in 1984, has links to ISIS, whose members carried out attacks in Paris on Nov. 13, killing 130 people. Frodermann said authorities were warned about Abdalhmeed by a Syrian national, who had seen an article on a website, linking him to ISIS.

The website had cited a Syrian opposition activist and two others, who told the Journal that he was a mid-ranking official in the militant group and ran a money-transfer operation. Abdalhmeed was also believed to have been responsible for smuggling medicines and ammunition from Turkey. Others contacted by the Journal said that his relatives were also linked to the group.

Mohammad Alalaw, who was approached by the Journal, said that Abdalhmeed was one of the first people to have pledged allegiance to ISIS, even before it started gaining power in the region. He added that before ISIS, Abdalhmeed was a member of the Free Syrian Army until 2013.

Bettina Jendrusz, deputy head of the Unna-Massen shelter operated by the German Red Cross, told the Journal that Abdalhmeed reached Germany on Dec.2 and had given his name as Leeth Alrjab and stayed at the camp with four family members. Jendrusz added that it was common for refugees to change their names when they applied for asylum. She also said that Abdalhmeed was yet to be fingerprinted and undergo police checks while it was also not clear which of his relatives accompanied him to Germany.

The Paris attackers are believed to have entered Europe through Greece, posing as refugees. The attack and movements of the attackers led European countries to review the procedure used to allow refugees in and the security protocols followed to check them.

While Chancellor Angela Merkel's open-door refugee policy has been applauded by many, it has also been criticized by others, who feel that ISIS members or followers may be hiding among the refugees. About a million refugees, mostly from Syria, have so far entered Germany while several others have it as their destination due to its refugee-friendly policies.

“We mustn’t regard refugees with a general suspicion. But it’s also true that concerns aren’t unfounded that some potential threats might be among refugees,” Wolfgang Bosbach, a lawmaker with Merkel’s Christian Democratic Union party, said. “We must specifically emphasize the issue of [refugees’] valid identification to avert threats.”

Earlier this week, two people were arrested at a refugee shelter in the western Austrian city of Salzburg.